Fixed bed catalyst draw-off method and apparatus



April 14, 1953 E. H. ATwoOD ET Al. 2,635,071

FIXED BED cATALYsT DRAW-DFF METHOD AND APPARATUS Filed April 30, 1949 Patented Apr. 14, 1953 *UNITED STATES PATENT OFFICE FIXED BED CATALYST DRAW-OFF METHOD AND APPARATUS Edwin H. Atwood and Edward D. Keiper, Jr., Woodbury, N. J., assignors to Socony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporation of New York Application April 30, 1949, Serial N o. 90,658

7 Claims.

a suitable period of time, requisite for the desired products, removing the converted hydrocarbons therefrom. The reactions` are normally endothermic, requiring the addition of heat to the case to initiate and continue the conversion of the hydrocarbon charge. Some of the heat required may be stored in the particle-form contact material during regeneration. The remainder may be supplied by forcing a temperature-controlled fluid through appropriately placed tubes of a heat exchanger located inside the chamber or case. During the conversion cycle the particleformed material graudally becomes fouled by deposition of coke or carbonaceous material on the surface of the catalyst. The supply of reactant fluids to the case is stopped and combustion supporting gas is provided in its place to burn ofi these detrimental deposits and restore the catalyst substantially to its former activity. The temperature is prevented from rising to a point where the catalyst would be permanently damaged by passing cooling uid through the above described heat exchanger tubes during the regeneration cycle. By this method the catalyst is restored practically to its former activity, and this process can 'be repeated for a period of time until the catalyst becomes spent and no longer usable.

The removal of the spent catalyst from in situ conversion cases has heretofore entailed the eX- penditure of yconsiderable time and labor. It is customary to partially or completely disassemble the chamber, remove many or all of the tubes located therein and then remove the contact material through various ports in the wall of the vessel.

The object of this invention is to provide an improved method and apparatus for removing particle-form contact material from a conversion case. Another object of this invention is to provide a method of modifying apparatus commonly used for in situ conversion of hydrocarbons to provide for faster and easier removal of the spent particle-form contact material.

In order to illustrate the invention reference will 'be made in the following description to the attached drawing by reference numbers.

The drawing is a vertical section of a conversion case in highly diagrammatic form. A limited number of tubes are shown for clarity.

The conversion case comprises a cylindrical 2 body II), an enclosed top I I and an enclosed bottom I2. The top I I and bottom 2 may be removed from the body I0 to permit removal of the partitions, tube sheets and tubes. The cylindrical body I0 is mounted vertically and is cut transversely by partition plates I3, I4 which form the top and bottom of the reaction zone I5. The partition plates I3, I4 may be perforated to permit the passage of reactant fluid while preventing the passage of particle-form contact material although other means of vapor introduction andA removal are usually used. The tube sheets I6, Il are located below the lower partition plate I4 also cutting the cylindrical bodyy transversely. The upper tube sheet IE is located a spaced distance lbelow the lower partition plate I4 thereby providing a vapor inlet manifold I8. The lower tube sheet Il is spaced below the upper tube sheet I6, providing an outlet manifold I9 for the cooling fluid, usually a molten salt. The space below the lower tube sheet I'I serves as an inlet manifold 20 for the cooling fluid.

In operation the reaction zone is lled with contact material through the catalyst loader 2I, a tube passing from the outside of the case through the upper partition I3 into the reaction zone. The loader is then sealed by closing the inlet opening with a suitable cap 22 or plug.

The heat transfer fluid is introduced into the inlet manifold 2|] through the inlet conduit 23, from a source not shown. The fluid may be a molten alloy or more suitably a molten salt such as, for example, sodium and/or potassium nitrate or nitrite. The uid passes upwardly through a multitude of open ended tubes 24 which are projected into the reaction zone. These tubes 24 are partially enclosed by concentric tubes 25, which are closed at their upper ends and pass through the upper tube sheet I6 at the lower open ends. Thus the fluid can flow downwardly in the annulus between the concentric tubes into the outlet manifold I9. The transfer uid is withdrawn through the outlet conduit 26 to the other apparatus not shown.

The reactant fluids, properly prepared for conversion, are admitted to the inlet manifold I8 through the inlet ports 21, located around the periphery of the case body I Il. About four to eight ports are normally required for this purpose.

The vapors pass upwardly through the perforated vapor tubes 28, passing through the orifices into the reaction zone wherein they contact the catalyst and are converted. The products are withdrawn from perforated tubes 29, depending from the upper partition plate I S into an outlet manifold 30. The vapors pass upwardly through the olllitlet port 3I to other processing apparatus, not s own.

The catalyst unloading tubes 32 are generally vertical and connect the reaction zone with the catalyst removal conduit 33. In the familiar in situ cases, approximately 12-20 unloading tubes are required to give satisfactory catalyst remo-val. In order to maintain proper catalyst-exchanger surface relationship, dummy-vapor tubes 34 can be suspended over the catalyst unloadingtubes 32, within the reaction zone. These tubes have a closed upper end to prevent catalyst from enter ing during the catalyst loading step.

Before filling the empty case with catalyst, an inert refractory material 35 such as, for example, corehart, mullite, or other inertmaterial, in par# ticle form, is introduced into the case to iill the catalyst unloading tubes 32 and to cover the lower partition plate I4 to a depth of about 1/2 to 2". This material may be in the shape of pellets, fragments, or cubes, etc. It is preferred, however, that the material be in the form of substantially spherical balls of about g" to 1A." in diameter.

During the conversion stage of the cycle, steam or other fluid is admitted through the conduit 35 into .the funnel shaped adapter 37, thereafter fio-wing upwardly through the catalyst unloading tubes into the reaction Zone. By maintaining the pressure in conduit 36 higher than the pressure inthe reaction zone a positive flow of steam into the reaction Zone is assured. This prevents the reactive fluids from contacting the unloading tubes 32 and the refractory balls 35, preventing the deposition of carbonaceous deposits thereon. The tubes 32 are thus kept free and open, ready for the removal of catalyst therethrough when required. It is desirable to limit the steam flow into the reaction zone to that required to prevent reactant uids from entering the unloading tubes 32. The pressure lines 38, 39, shown by dashed lines, -convey the reactio-n zone pressure, and inlet conduit pressure to a valve controller 40, shown diagrammatically in block form. The valve controller 40 can be adjusted to operate valve 4l in the conduit 36 to maintain any desired and suitable pressure differential. The valve oontroller is keyed intoI the cycle timer, not shown, to keep Valve 4l closed, except during the conversion stage of the cycle. The cycle timer, above referred to, controls the apparatus to change the stage from conversion to regeneration at the required time. Thus, at that time, co-mbustion supporting gas is admitted through the vapor inlet ports instead of reactant fluids, burning the deposits from the catalyst in the reaction zone to reactivate the catalyst.

' When it is necessary to unload the catalyst, the block valve 42, normally closed, is opened fully, and the flow of material therefrom is controlled by the cock valve d3. The refractory balls 35 flow freely from the tubes, and the catalyst particles follow. Without great labor and in a short period 4 and a vapor inlet manifold located below said lower partition plate, a lower tube sheet located a spaced distance below said upper tube sheet adapted to divide the lower section of the vessel into upper and lower exchanger fluid manifolds, exchanger tubes located within said reaction zone and communicating with said upper and lower exchanger fluid manifolds, catalyst unloading tubes located in the lower section of said vessel, the upper end of said tubes projected through the lower partition plate and communicating with the reaction zone, an outlet conduit located below said vessel, the lower ends of said unloading tubes connected to said outlet conduit and communieating therewith, closure means in said outlet conduit, means for introducing fluid into said conduit above said closure means, means for controlling the flow of fluid introduced into said conduit, and inert particle-form refractory material located inside said conduit above said Y closure means, inside said unloading tubes, and

of time the reaction zone is substantially drainedA of catalyst. By this method approximately 95% of the catalyst is removed, and the case is rapidly prepared for refilling. The inert balls 35 can readily be separated from the spent catalyst and reused for the next charge.

We claim:

l. An improved in situ hydrocarbon converter comprising a vertically mounted vessel, upper and lower partition plates horizontally mounted in said vessel to define a reaction zone, means for introducing particle-form material into said zone,l

an upper tube sheet spaced below said lower partition plate, said plates definingv a vapor outlet manifold-*located above said upper partition plate on the surface of said lower partition plate below the bed of particleeform catalyst material.

2. Apparatus for in situ conversion of hydrocarbons comprising in combination a vertically mounted chamber having side walls, a top, and a bottom, upper and lower partition plates hori- Zontally located within said chamber defining a reaction Zone, said upper partition plate defining a vapor outlet manifold above said plate, an upper and lower tube sheet horizontally located spaced distances below said lower partition plate, said lower partition plate and upper and lower tube sheets dividing said chamber into a reactant vapor manifold, upper and lower heat exchanger fluid manifolds, heat exchanger tube assemblies vertically mounted within said chamber cornprising an outer tube closed at the upper end, the upper end projected into the reactio-n zone, the lower end projected into the upper heat exchanger fluid manifold and communicating therewith, an inner tube open at both ends concentric with said outer tube, the lower end projected into the lower heat exchanger fluid manifold and communicating therewith, the upper end communicating with the interior of said outer tube, vertically mounted perforated Vapor transfer tubes located within said reaction zone, said tubes closedA at one end, the inlet vapor tubes passing through the lower partition plate and communicating with the reactant vapor manifold, the outlet vapor tubes passing through the upper partition plate and communicating with the vapor outlet manifold, means for admitting particle-form catalyst to the reaction Zone, an outlet conduit attached to the bottom of said chamber, catalyst unloading tubes open at both ends located in the lower portion of the chamber, the upper ends of the tubes communicating with the reaction zone, the lower ends of the tubes communicating with the outlet conduit, means for stopping the flow of catalyst through said outlet conduit, means for introducing fluid to said outlet conduit at a location above said ow stopping means, means for controlling the flow of fluid introduced into said conduit, and inert particle-form material located on the surface of said lower partition plate, the interior of said catalyst unloading tubes, and the interior of said outlet conduit above the flow stopping means.

3. In apparatus for hydrocarbon conversion comprising a vertically mounted vessel, transverse upper and lower partition plates defining a reaction Zone within said vessel, transverse upper and lower tube sheets located spaced distances below said lower partition plate, inlet ports through the wall of said vessel to admit reactant fluid to the reactant fluid manifold formed between said lower partition plate and said upper tube sheet, said upper and lower tube sheets defining manifolds between said tube sheets and between said lower tube sheet and the bottom of said vessel, heat exchange tube assemblies cornprising an inner tube open at both ends projected into the reaction zone at its upper end and through said lower tube sheet at its lower end to communicate with said lower manifold, an outer tube surrounding said inner tube closed at its upper end and projected through said upper tube sheet at its lower end to communicate with said upper manifold, vertically mounted perforated inlet vapor tubes in said reaction zone projected through said lower partition plate at their lower ends to communicate with said reactant iiuid manifold, vertically mounted perforated outlet vapor in said reaction zone projected through said upper partition plate to co-mmunicate with the vapor outlet manifold formed above said partition plate with the top of the vessel, the improvement which comprises catalyst unloading tubes mounted in the lower section of said vessel open at both ends, the upper end communicating with the reaction Zone, a funnel-shaped adapter :attached to the lower ends cf said unloading tubes, said funnel-shaped adapter having a top wall through which the lower ends of said unloading tubes are projected to co-mmunicate with the interior of said adapter, an outlet, conduit attached to the lower end of said adapter and communicating therewith, a valve in said outlet conduit, an inlet conduit attached to said adapter and communicating therewith, a valve located in said inlet conduit, particle-form inert refractory material located in said unloading tubes, adapter and the portion of said outlet conduit above said valve.

4. The process of removing particle-form catalyst from an in situ converter 'in which unloading conduits have been installed connecting the lower portion of the reaction zone of the converter with the bottom exterior of the vessel which comprises closing the outlets of said unloading conduits, filling the conduits and lower portion of the converter reaction Zone with inert refractory material, introducing particle-form catalyst into the reaction zone, introducing inert uid, which exists in the vapor state under the pressure and temperature of the reaction zone, into the reaction zone through the unloading conduits during the conversion, and opening the outlets of said unloading conduits after the activity of the particle-form catalyst is reduced to the desired limit to drain the major portion of the converter particle-form catalyst from the reaction zone.

5. The process of removing particle-form catalyst from the reaction zone of an in s1tu converter in which said converter possesses a multiplicity of unloading tubes connecting the bottom of the reaction zone with an outlet conduit located below the converter which comprises closing the outlet conduit and introducing inert refractory material in particle form into the outlet conduit, the interior of said unloading tubes, and the lower portion of said reaction zone prior to the introduction of said particle-form catalyst, introducing particle-form catalyst into. said reaction zone, introducing inert fluid, which exists in the vapor state under the pressureand ternperature of the reaction zone, into said conduit 6 during the conversion process in suflicient quantity to prevent reactant fluids from entering the unloading tubes, and opening the outlet cc-nduit after the activity of the particle-form catalyst is reduced to the desired limit to drain the inert refractory material and substantially all the particle-form catalyst from the reaction zone of said in situ converter.

6. The method of operation of an in situ hydrocarbon convertor which provides for easy removal of the spent catalyst from the reaction zone after a series of cycles in which the catalyst particles are contacted alternately with a stream of hydrocarbons to effect conversion to lighter hydrocarbons and with a stream of combustion-supporting gas to effect regeneration of the solids until the catalyst particles become substantially spent and require replacement which comprises: maintaining a thin layer of inert particle form material on the bottom of the reaction zone beneath the bed of catalyst, so as to provide a support for the catalyst, maintaining a multiplicity of vertical columns of inert particle form material beneath the reaction zone at locations uniformly distributed about the bottom of said zone and in open communication with said zone, introducing an inert gas into the lower ends of said columns of inert material at a pressure just above that in the reaction zone whenever hydrocarbons are introduced into the reaction zone, so as to substantially prevent hydrocarbon vapors from contacting the inert particles, and withdrawing solid particles from the bottom of said columns when the catalyst in said reaction zone is substantially spent, so as to rapidly drain the reaction zone of both inert and catalytic particles.

7. In an in situ hydrocarbon convertor which comprises a vessel having upper and lower partition plates horizontally mounted within said vessel to define a reaction zone therebetween. the improvement which comprises: an outlet conduit located below said vessel, a multiplicity of generally vertical unloading tubes mounted in said vessel, having their upper ends attached to the lower partition plate at locations uniformly distributed across said plate and having their lower ends attached to said outlet conduit, closure means in said outlet conduit, means for introducing fluid into said conduit above said closure means, means for controlling the iiow of fluid introduced into said conduit and inert particle-form refractory material located inside said conduit above said closure means, inside said unloading tubes, and on the surface of said lower partition plate, in the form of a thin layer of inert particles supported by a multiplicity of unobstructed laterally confined columns of inert particles which are in turn supported by a laterally confined column of said inert particles, so as to provide a oor for the bed of contact caltalyst between the partition plates in said vesse EDWIN H. ATWOOD.

EDWARD D. KELPER, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,195,738 Ridler et al. Apr. 2, 1940 2,212,583 Broderson et al. Aug. 27, 1940 2,376,629 Stanfield et al. May 22, 1945 2,432,543 Prickett et a1. Dec. '16, 1947 

6. THE METHOD OF OPERATION OF AN IN SITU HYDROCARBON CONVERTOR WHICH PROVIDES FOR EASY REMOVAL OF THE SPENT CATALYST FROM THE REACTION ZONE AFTER A SERIES OF CYCLES IN WHICH THE CATALYST PARTICLES ARE CONTACTED ALTERNATELY WITH A STREAM OF HYDROCARBONS TO EFFECT CONVERSION TO LIGHTER HYDROCARBONS AND WITH A STREAM OF COMBUSTION-SUPPORTING GAS TO EFFECT REGENERATION OF THE SOLIDS UNTIL THE CATALYST PARTICLES BECOME SUBSTANTIALLY SPENT AND REQUIRE REPLACEMENT WHICH COMPRISES: MAINTAINING A THIN LAYER OF INERT PARTICLE FORM MATERIAL ON THE BOTTOM OF THE REACTION ZONE BENEATH THE BED OF CATALYST, SO AS TO PROVIDE A SUPPORT FOR THE CATALYST, MAINTAINING A MULTIPLICITY OF VERTICAL COLUMNS OF INERT PARTICLE FORM MATERIAL BENEATH THE REACTION ZONE AT LOCATIONS UNIFORMLY DISTRIBUTED ABOUT THE BOTTOM OF SAID ZONE AND IN OPEN COMMUNICATION WITH SAID ZONE, INTRODUCING AN INERT GAS INTO THE LOWER ENDS OF SAID COLUMNS OF INERT MATERIAL AT A PRESSURE JUST ABOVE THAT IN THE REACTION ZONE WHENEVER HYDROCARBONS ARE INTRODUCED INTO THE REACTION ZONE, SO AS TO SUBSTANTIALLY PREVENT HYDROCARBON VAPORS FROM CONTACTING THE INERT PARTICLES, AND WITHDRAWING SOLID PARTICLES FROM THE BOTTOM OF SAID COLUMNS WHEN THE CATALYST IN SAID REACTION ZONE IS SUBSTANTIALLY SPENT, SO AS TO RAPIDLY DRAIN THE REACTION ZONE OF BOTH INERT AND CATALYTIC PARTICLES. 